WorkedRated 5 out of 5 stars

Fresh install of FF, no other addons, worked to fix broken IdenFavIcon. I only run a few other addons, primarily xmarks and lastpass and adblockplus. In the many years I've run those addons, they've always played nice with all other addons.

I'm sorry to hear that, but I'm pretty certain that it is related to some other extension you have installed. Could you please double check with a clean profile, installing identfavicon in itself and testing if it works that way? Alternatively, you can just simply disable all other extensions.